The initial reactions utilized by bacteria to oxidize aromatic hydrocarbons from the main substance of the project. At this time bacteria have been shown to oxidize aromatic hydrocarbons to cis-dihydrodihydroxy derivatives. Both atoms of oxygen in these derivatives are supplied by a single molecule of atmospheric oxygen. The enzyme systems that form cis-2,3-dihydroxy-2,3-dihydrotoluene and cis-l,2-dihydroxy-l,2-dihydroNaphthalene are being purified and characterized as are the enzymes that incorporate atmospheric oxygen into dihydroxy aromatic compounds. The above enzymes oxidize a variety of different substrates. The products formed will be isolated and their structures determined. Since most of the reaction products formed from aromatic compounds contain assymmetric carbon atoms an enzymatic method is being developed to determine the absolute stereochemistry of these metabolites. The initial reactions utilized by bacteria to oxidize polychlorinated biphenyls and aromatic sulfur compounds are being investigated.